Fluidic gaging sensor head

ABSTRACT

The sensor head component of an apparatus for monitoring a selected parameter of a continuous material such as yarn, metal rod, tubing and the like, includes a fluidic long, narrow channel for passage of the material therethrough. Pressurized fluid is supplied to the center of the channel formed by a cover plate member and slotted plate member. Passage of the monitored material through the channel varies the restriction thereof in proportion to the magnitude of the monitored parameter and develops a variable back pressure linearly proportional thereto. A toggle clamp provides alternate engagement with and separation of the plate members. A spring device connected to the cover plate member provides a means for loading and threading a yarn material in the sensor head without stopping the longitudinal motion of the yarn.

United States Patent Czwakiel et-al.

[ 1 June6,1972

[54] F LUIDIC GAGING SENSOR HEAD [73] Assignee: General Electric Company[22] Filed: Feb. 18, 1970 21 Appl. No.: 12,289

l l Relcrences Cited UNl'l lil') .i'l A'l'l'lS PATENTS 2,402,293 6/1946Nye ..73/37.7X 3,199,339 10/1965 Lipski.. 73/377 3,282,085 11/1966Benson et a ..73/37.7

Primary Examiner- Louis R. Prince Assistant Examiner-William A. Henry,ll

AltorneyDavid M. Schiller, Arthur E. Foumier, .Ir., Frank L. Neuhauser,Oscar B. Waddell and Joseph B. Forman [57] ABSTRACT The sensor headcomponent of an apparatus for monitoring a selected parameter of acontinuous material such as yarn, metal rod, tubing and the like,includes a fluidic long, narrow channel for passage of the materialtherethrough. Pressurized fluid is supplied to the center of the channelformed by a cover plate member and slotted plate member. Passage of themonitored material through the channel varies the restriction thereof inproportion to the magnitude of the monitored parameter and develops avariable back pressure linearly proportional thereto. A toggle clampprovides alternate engagement with and separation of the plate members.A spring device connected to the cover plate member provides a means forloading and threading a yam material in the sensor head without stoppingthe longitudinal motion of the yarn.

5 Claims, 3 Drawing Figures PATENTEUJUN 61972 I 3,667, 282

20 ,5; Z g I JA FLUIDIC GAGING SENSOR HEAD Our invention relates to asensor head component of an apparatus for continuous monitoring of aselected parameter such as outside diameter, cross sectional area ordenier of a continuous, small cross section material, and in particular,to a fluidic gaging sensor head adapted for threading the monitoredmaterial through the sensor head without stopping the longitudinalmotion of such material.

A fluidic gage apparatus for continuous monitoring of a particularparameter such as wire diameter, sliver density and the like isdisclosed and claimed in a copending U.S. Pat. application Ser. No.800,623, to Hansjoerg Stern, filed Feb. 19, I969 and assigned to theassignee of the present invention. The sensor head employed in suchearlier apparatus is satisfactory but lacks the capability of beingadapted for threading or loading the sensor head while the monitoredmaterial is continually moving in the longitudinal direction. A gagingapparatus for continuous in-process monitoring desirably should havethis capability without stopping the motion of the monitored materialfor purposes of achieving a maximum rate of production of such material.

Therefore, one of the principal objects of our invention is to providean improved sensor head component of a gaging apparatus which is capableof being threaded or loaded, while the material is in motion.

The sensor heads disclosed in the foregoing patent application to Sternare of the sharp orifice type which do not provide a laminar flow ofpressurized fluid through the gaging channel of the sensor head andtherefore does not result in a linear relationship between themagnitudes of an induced back pressure and the selected monitoredparameter, as is desired in many cases.

Therefore, another object of our invention is to provide the sensor headwith a channel adapted for developing a laminar flow of pressurizedfluid therein.

Finally, in the case of monitoring a multi-strand continuous yarnmaterial such as a thread or sliver, no prior art is known for adoptinga sensor head to rapidly collect the individual strands and force theminto the channel of the sensor head in the threading operation.Therefore, a still further object of our invention is to provide thesensor head with a spring loader device operative only during thethreading or loading operation of the monitoring apparatus.

Another object of our invention is to provide a new method for loadingor threading the sensor head with the material to be monitored whilesuch material is in motion.

In accordance with the object of our invention, we provide a sensor headcomponent which includes a slotted plate member having a first slotted.surface and a cover plate member having a first nonslotted surface. Inthe engaged state of the two plate members, the first surfaces form achannel therebetween for passage of a small cross section, continuousmaterial being monitored by the sensor head. Pressurized fluid issupplied to the center of the channel to cause a laminar flow of thefluid toward the two ends of the channel, the flow being restricted bythe monitored material passing therethrough and developing a backpressure at the point of issuance of the fluid into the channel. Themagnitude of the back pressure varies linearly with the magnitude of theparticular parameter being monitored. A mechanical arrangement such as atoggle clamp provides a hold-down action for obtaining mating of theplate members in the engaged state thereof. A retractable spring loaderdevice may be connected to the cover plate member for collecting andforcing a yam-like material being monitored into the slot during thethreading or loading operation wherein the cover plate member isseparated from the slotted plate member and then initially engaged in anonlocked position.

The features of our invention which we desire to protect herein arepointed out with particularity in the appended claims. The inventionitself, however, both as to its organization and method of operation,together with further objects and advantages thereof may best beunderstood by reference to the following description taken in connectionwith the accompanying drawing wherein like parts in each of the severalfigures are identified by the same reference character and wherein:

FIG. 1 is a perspective view of the sensor head constructed inaccordance with our invention illustrating the separated state of thecover and slotted plate members and a tubing material to be monitoredthereby;

FIG. 2 is a side view of the engaged state of the cover and slottedplate members of the FIG. 1 sensor head with the addition of aretractable spring loader device shown in its nonretracted position; and

FIG. 3 is a perspective view of the sensor head shown in FIG. 2 with theretractable spring loader in its retracted position and a yarn materialbeing monitored.

Referring now in particular to FIG. 1, there is shown our sensor headadapted for monitoring, and, or, gaging, the outside diameter of atubular material 10 which may be metal, plastic or virtually anymaterial nonreactive with a fluid medium employed in the sensor head.The arrow heads indicate one direction of motion of the monitoredtubular material through the sensor head, it being understood that thelongitudinal motion may also be in the opposite direction since thesensor head is of symmetrical construction. The sensor head is acomponent of an apparatus which permits continuous, nondestructivein-process monitoring, and if desired, gaging, of a particular parameterof the continuous material passing through the sensor head. Thus, theapparatus may be employed merely for monitoring (i.e., detecting changesin the outside diameter of) tubing 10, or for the gaging (i.e.,measuring the outside diameter) thereof.

The sensor head is basically comprised of a slotted plate member 1 1having a first slotted surface 11a, and a cover plate member 12 having afirst nonslotted surface 124. Slot 13 is disposed at approximately thecenterline of surface 11a and extends entirely thereac'ross, preferablyin the longest direction thereof. Surfaces 1 la and 12a, when engaged inmating relationship, form a channel defined by slot 13 and the portionof surface in direct communication therewith. Members 11 and 12 may beof any shape, although they preferably are of the same general shape,our preferred embodiment being rectangular. Member 12 preferably has alength dimension slightly exceeding that of member 11 such that member12 slightly overhangs member 11 at the ends thereof for purposes ofinsuring a more positive loading of the tubular material into slot 13.The overhanging sides of member 12 have a rounded lower edge to minimizethe possibility of such edge damaging the monitored material with whichit may occasionally come in contact. Slot 13 is straight andequidimensioned along the length thereof, although it is preferablyprovided with flared ends for ease of entrance and exit of the materialbeing monitored. In addition, the central region 13a of the slot may beof slightly enlarged dimension, as illustrated, for ease of admission ofa pressurized fluid in-. troduced into the slot in the engaged state ofthe slotted and cover plate members as hereinafter described. A slightextension of hole 13a is formed approximately one-eighth inch intosurface 12a as shown in FIGS. 1 and 2 as 12a. The ratio of slot lengthto width is at least 10:1 to assure a laminar flow of the fluid from thecentral region to the two outer ends thereof. The channel formed by theslot thus is an effective laminartype fluid restrictor which provides avariable restriction to fluid flow therethrough in accordance withvariable dimensions in the tubular material passing therethrough. Thelaminar flow is desired since it provides a linear relationship of themonitored parameter and the fluid back pressure induced at centralregion 13a by the restrictive effect of the material passing through thechannel. The cross-sectional area and width of slot 13 is slightlylarger than the largest anticipated area and width of the material beingmonitored. The cross section outline of slot 13 also generally conformsto that of the monitored material. Thus, in the specific applicationillustrated in FIG. 1 wherein monitored material 10 is a metal tubing,the cross section of slot 13 is semicircular near the bottom and aslight vertical extension near the top as more clearly indicated in theside view of FIG. 2. Alternatively, the cross section of slot 13 may bemerely semicircular, but in such a larger radius would be necessarysince the monitored material is circular in cross section and loadedinto the slot from the top. It can be appreciated that in the case ofmaterial being a square cross section rod, the cross section of slot 13is preferably a larger square or rectangular.

The pressurized fluid, which may be a gas such as air or liquid such aswater, is supplied to the central region 13a of the enclosed channelfrom an external source of the pressurized fluid by any convenientmeans. As one example, not to be considered a limitation of such means,a base member 14 is connected to the bottom of slotted plate member 11which is the surface opposite from the slotted surface 11a. Base member14 may have any of a number of shapes, the illustrated one beinggenerally rectangular and having an upper surface including a depressedregion 14a which serves to retain slotted plate member 1 1 in its properorientation. Members l l, 12 and 14 may be fabricated of materials suchas aluminum, stainless steel, plastic,' and the like, the particularmaterial being governed in part by the material 10 being monitored andthe environment of operation. Member 14 has a thickness (heightdimension) greater than that of plate members ll, 12 and is providedwith a passage 15 (shown in dashed outline) formed into its side andpassing horizontally inward toward the center thereof in the orientationof the sensor head illustrated in FIG. 1. This internal passage 15 isthence formed vertically upward from the center region of member 14 andpasses into slotted plate member 11 terminating in a port at the slotcentral region 13a. Depending upon the diameter of this internal passage15 relative to the width dimension (in cross section) of slot 13, thejuncture of passage 15 and slot 13 may result in the enlarged region 13aof the center of slot 13. A suitable fitting 16 is fastened in anyconvenient manner into the side of member 14 for connection with acoupling 17 connected to the end of a conduit 18 which in turn isconnected to the source (not shown) of the pressurized fluid. lntemalpassage 15 therefore forms a confined passage for fluidically couplingfitting 16 to the port at the center of slot 13. Base member 14 may beconnected to the bottom of plate member 11 in any convenient form, twomachine screws and associated washers being utilized as one example asindicated in FIG. 2. Rubber gasket 23 assumes a fluid-tight seal betweenmembers 11 and 14.

The plate members 11 and 12 of our sensor head are in the separatedstate illustrated in FIG. 1 when in the process of loading or threadingthe material 10 into the head and are in the engaged state illustratedin FIG. 3 during the monitoring mode of operation. Plate members 11 and12 are alternately engaged in mating relationship and separated by anyconvenient means which readily accomplishes this function in a minimumtime and with minimum effort. As one example of such means, aconventional toggle clamp 19 of the quickrelease type is especially welladapted for this application in providing a hold-down action in theclosed and locked state thereof. Toggle clamp comprises an actuatingmember 190, an actuated member 19b, a linkage 190 for coupling members19a and 19b, and a nonmovable base member 19d. Actuating member 19a is afirst lever arm having a handle or actuating end 19a and a fulcrum end19a" connected to base member 19d. Actuated member 1912 is the drivenelement of the clamp and is a second lever arm having a driven end 19bconnected to the top surface of cover plate member 12, and a fulcrum end19b" connected to base member 19d. Linkage 19c connects the two leverarms and is oriented with respect thereto such that pressing down onhandle end 19a with a minimum force causes driven end 19b to movedownward until surfaces 1 la and 12a are engaged in mating relationshipbut in an unlocked state; further depression of handle end 19a causeslinkage 19c to force surfaces 11a and 12a to be engaged in a lockedstate. Clamp base member 19d is connected to sensor head base member 14by means of four machine screws and associated washers. Driven end 19bof lever arm 19 is connected to cover plate member 12 by means of ashoulder screw 11a and a pair of rubber washers 22b.

Base plate member 14 may also be provided with additional fluid passages15a formed through opposite sides thereof as illustrated in dashedoutline in FIG. 1. Such additional passages are normally plugged whennot in use since they have a common juncture with passage 15 in theregion where such passage changes direction from horizontal to vertical.Member 14 is further provided with at least one mounting hole 20 forsupporting the sensor head slotted plate member 11 and base member 14 ina stationary position. Mounting hole 20 is internally threaded and mayconveniently be disposed toward the rear of one or both sides of member14 as illustrated in FIG. 2 and also in the back end of member 14 formounting on a suitable fixed support. such as partially threadedmounting rod 21. The preferred embodiment of our sensor head is providedwith all three of the mounting holes to permit greater latitude inmounting arrangements for the sensor head. A

The operation of our sensor head as illustrated in FIG. 1 will now beexplained. The sensor head component of the monitoring apparatus ismounted in the required orientation such that slot 13 is aligned with acontinuous material 10 to be monitored by the apparatus. The material 10is loaded or threaded into the sensor head in the following manner. Flowof the pressurized fluid through conduit 18 to the sensor head ispreferably, although not necessarily, stopped by any suitable means.Toggle clamp 19 is initially in its open position as illustrated in FIG.1 and the material 10 is forced downward into slot 13 of slotted platemember-11. Upon the material being disposed within slot 13, it beingrecognized that the material may be continually moving in thelongitudinal direction indicated by the arrow heads during the threadingoperation, the toggle clamp is operated into its closed and lockedposition. Upon locking of the toggle clamp, there is initiation of flowof the pressurized fluid through passage 15 to central region 13a of thechannel through which material 10 is moving. The pressurized fluid flowsin a laminar mode from central region to the atmosphere at the outerends of the channel. The variable restriction to the laminar fluid flowcaused by the variable dimensions of the monitored material continuallymoving through the channel develops a variable back pressure in region13a. The magnitude of the back pressure induced at center 13a isdetected by a suitable circuit or device having an input connected toconduit 18. Monitored materials such as yarn and slivers that are belowa desired denier, or filaments, wires, threads, ropes and rods that arebelow a desired diameter, present less than normal flow resistance,causing a lower induced pressure while the converse is true if themonitored material is of higher denier or of larger diameter. Thus, a

change in induced pressure is directly proportional to a change indenier or diameter of the monitored material. These small pressurechanges are amplified by suitable analog-type fluid amplifier circuitryand recorded, or may be converted to electrical signals, amplified, andthence recorded on a suitable device such as strip chart recorder.

In a specific embodiment of the sensor head illustrated in FIG. 1 (andFIGS. 2 and 3) which is adapted for continuous on-line monitoring ofnatural or synthetic fiber materials, metal wire, tubing, and the like,slotted plate member 11 has a length of 3 :6 inch, width of l /6 inchand height of one-fourth inch. Slot 13 in cross section along theequidimensioned portion thereof is a semicircle having a radius of 0.021inch, the center of the semicircular are being displaced 0.021 inchbelow surface 1 la. The ends of slot 13 flare out at an angle of 30 fromthe longitudinal axis of slot 13 and terminate at the sides of platemember 11 at a 0.25 inch diameter. The central region 13a of slot 13 hasa diameter of 0.159 inch which equals the diameter of the passagedrilled through members 11 and 14 for communication with conduit 18.Cover plate member 12 has width and height dimensions equal to that ofmember 11, and a length of 3 Y4 inch. Base member 14 is 1 6 inch in thelength direction of plate members 11 and 12, 2 inches in the widthdirection, and heights of three-eighths inch (below plate member 1 1)and one-half inch (below the base of toggle clamp 19). Pressurized airat a relatively constant pressure of 1.0 psi gauge is supplied to thesensor head through conduit 18. As an indication of the sensitivity ofour sensor head, a change in diameter or denier of the monitoredmaterial of i 1 percent can readily be detected at the supply pressureof 1.0 psig. It should be apparent that sensitivity is improved withincreased supply pressure. Finally, the sensitivity must also beconsidered relative to the entire monitoring apparatus and therefore isalso dependent on the degree of amplification of the induced pressuresignal and the type of read-out employed in the apparatus. 1

In general, sensor heads constructed in accordance with our inventionare capable of monitoring, and, or gaging materials which pass throughat speeds of up to 5,000 feet per minute and higher. A speed of 15,000feet per minute has been attained, and the maximum speed is governedprimarily by the required response and sensitivity to a given lengthparameter change in the material being monitored. The sensor head iscapable of monitoring a minimum diameter of 0.0025 inch, there being nomaximum diameter limitation. It should be evident that in the case offiber materials, the sensor head is suitable for monitoring and, or,gaging parameters such as diameter, cross sectional area, and indirectlydenier. The continuous on-line monitoring of the material can be madewherever access to the material is available. In the specific case ofmonitoring fibers in the textile industry, our invention avoids thepresent time consuming operation of stopping a fiber line, cutting,transporting and weighing the fibers in order to run a quality check.The monitoring apparatus is compatible with a variety of differentdiameter materials to be monitored, comparable sensitivity over a widerange of material cross sectional areas, being attained by interchangingslotted plate member 11 with another one having a more suitable slotdiameter, or alternatively, the entire sensor head may readily bereplaced by dismounting from the mounting means 21 and disconnecting thefitting 16 from coupling 17. In the case wherein the sensor headutilizes pressurized air, it has the advantage of being adapted for usein hazardous environments. The sensor head is suitable for use in areasof severe vibration high temperature and high humidity.

FIG. 2 is a side view of the engaged but unlocked state of the FIG. 1sensor head and is further provided with a loading or threading meansfor collecting the strands of a multi-strand yarn material which is tobe monitored by the apparatus and for forcing the collected strands intothe slot 13in member 1 1. The strand collecting and forcing meanscomprises a spring device 25 which is seen in FIG. 3 to include acentral spring member 25a, and a pair of identical end spring members25b and 250 formed at opposite ends of central spring member 250. Theend spring members may be separate elements but preferably are formedwith the central member from a single thin piece of metal such asstainless steel to be sufficiently resilient to exhibit a springcharacteristic. Spring device 25 is retained on the upper surface ofcover plate member 12 and coupled to toggle clamp driven lever arm 19bby means of shoulder screw 22a passing through a central hole in member25a. Rubber washers 22b act as flexure couplings between arm 19band-member 12 to accommodate any misalignment which would preventmembers 1 1 and 12 from sealing tightly. End spring members 25b and 25cextend beyond the sides of cover plate member 12 wherein the ends of thechannel 13 are disposed and the outer end portions of the end springmembers are bent downward and terminate in concave-shaped guides 25 dfor the monitored material. The concave-shaped guides 25d may be concaveshaped ends of spring members 25b, 250, but for purposes of minimizingthe possibility of damaging the monitored yarn material due to sharpedges of the spring member metal, guides 25d are preferably separateelements suitably attached to the ends of members 25b, 250. In theillustrated embodiment, guide members 25d are polished ceramic buttonshaving a removed concave-shaped lower portion (as viewed in FIG. 2)resembling a sector of a circle through which the monitored materialtravels. The ends of each of spring members 25b, 25c are formed into twoseparated arms 25e which are crimped. The ceramic guide buttons 25d areattached to the end arms 25e of spring members 25b, 250 by passing thesmaller diameter back end of the button between the arms and inserting apin 25f horizontally through the button back end at the upper inner edgeof the arm crimp whereby the inserted pin rests against the crimp andthereby retains the button in place. The lower surfaces of arms 25e bearagainst the backs of buttons 25d for further support thereof.

Central spring member 25a is crimped at the junctures with end members25b, 25c, and it can be visualized that this crimping functions todevelop a two-state mode of operation of spring device 25, and thereforealso of guide members 25d. Thus, in the separated state of plate membersll, 12 (open state of toggle clamp 19) end spring members 25b, 25c (andthus also guide members 25d) are also in an isolated position spacedfrom the longitudinal axis of slot 13 and monitored material 10. Theyarn material is assumed to be continually moving in a longitudinaldirection immediately above slot 13. An initial depression of handle end19a of the toggle clamp with a minimum of force causes the initialclosed but unlocked state of the clamp (and plate members 11, 12)described hereinabove wherein no significant force is impressed oncentral spring member 25a. In this closed but unlocked state of clamp19, guide members 25d have been forced downward such that theconcave-shaped portions thereof are now below the longitudinal axis ofslot 13 thereby collecting the strands of the yarn on the downwardstroke and forcing the collected strands into the slot (see FIG. 2).Upon the sensor head being threaded, handle end 19a is further depressedto achieve the closed and locked state of the clamp (and plate members11, 12). In the locked state the force exerted by linkage 19c exerts aforce on central spring member 25a which bows downward and reacts withthe crimps resulting in a retraction of end spring members 25b, 25c (andguide members 25d) to an upward position such that the guide members arespaced from the monitored yarn sufiiciently to not interfere therewith(see FIG. 3). This is the normal operating mode of the sensor had I whenmonitoring the material 10. Spring device 25 is sufficiently resilientsuch that any abnormally large increase in dimension of the material tobe monitored will cause a separation of plate members ll, 12 in theengaged but unlocked state thereof. Spring device 25 (and thus alsoguide member 25d) are retained in alignment with slot 13 by any suitablemeans, such as a pair of roll pins or dowels 25g passing through endspring members 25b, 25c along the center-line thereof and into coverplate member 12.

From the hereinabove description, it can be appreciated that ourinvention achieves the objectives set forth in that it provides animproved sensor head component which is capable of being threaded orloaded with the material to be monitored while such material remains inmotion. The long and narrow channel in the sensor head through which thematerial passes provides a laminar flow of the pressurized fluid throughthe channel resulting in a linear relationship between magnitude of theinduced back pressure and the selected parameter being monitored. Inaddition, this long and narrow channel with the material passingtherethrough presents a very high fluid flow resistance as opposed tothe use of sharp edged orifices and thus our sensor head is much moresensitive in detecting small changes in the monitored parameter andmaterial being a multi-strand yarn material which is first collected andthen forced into the slot while such material is still moving in itslongitudinal direction. Thus, our invention pro vides a nondestructivemonitoring of in-process quality changes of a variety. of materialswithout the necessity of stopping, or even slowing down such material.

Having described a specific embodiment of our sensor head, it isbelieved obvious that modification and variation of our invention ispossible in light of the above teachings. Thus, cover and slotted platemembers and base member may assume shapes other than the rectangularones disclosed, the only requirement being that the slot which forms theenclosed channel besufficiently long and small in cross section toobtain a high resistance to the fluid flow therethrough when thematerial is being monitored, and that a laminar flow be achieved toobtain the desired linearity between induced back pressure and monitoredparameter. Further, the pressurized fluid may be supplied to a passagein cover plate member for issuance into the central region 13a of thechannel. In some instances it may be desirable to utilize a slottedplate member 1 l of sufi'icient thickness such that base member 14 maybe eliminated. Finally, other types of devices for providing a hold-downaction to maintain members 11 and 12 in mating relationship and othertypes of guide members may be employed.

What we claim and desire to secure by Letters Patent of the UnitedStates of America is:

1. In an apparatus for monitoring a selected parameter of a small crosssection, continuous material suitable for passage through an improvedsensor had component of the apparatus, the improved sensor headcomprising,

a slotted plate member having a first slotted surface,

a cover plate member having a first nonslotted surface,

means for alternately engaging in mating relationship and separating thefirst surfaces of said slotted and cover plate members to thereby form achannel between said plate 7 members in the engaged state thereof,

.means for supplying a pressurized fluid to said channel centrallythereof, said channel being enclosed along its sides in the engagedstate of said plate members except for a port supplying the pressurizedfluid into said channel, said channel adapted for passage of a smallcross section, continuous material therethrough whereby the pressurizedfluid upon" issuance from said port restrictively flows along saidchannel from the center to the ends thereof, the back pressure inducedat said port resulting from the restriction caused by the materialpassing through said channel being proportional to he magnitude of aselected parameter of the material being monitored by the apparatus,

means for collecting the strands of a multi-strand yarn material beingmonitored by the apparatus and for forcing the collected strands intosaid slot in said slotted plate member, and said strand collecting andforcing means being retained on said cover plate member on a surfacethereof opposite from the first nonslotted surface, said strandcollecting and forcing means being operative with operation of saidalternately engaging and separating means.

2. The apparatus set forth in claim I wherein said strand collecting andforcing means comprises a spring device including a central springmember retained between the surface of said cover plate member oppositefrom the first nonslotted surface thereof and an actuated member of said7 alternately engaging and separating means, and

a pair of .end spring members connected at opposite ends of said centralspring member and extending beyond sides of the slotted and cover platemembers wherein the ends of the channel are disposed, the extremities ofsaid end spring members being concave-shaped and in an isolated positionspaced from the longitudinal axis of the slot during the separated stateof said plate members and being forced toward and beyond the axis in aninitial engaged state whereby the strands of the multi-strand yarnmaterial being threaded into the sensor head are collected by theconcaveshaped extremeties of said end spring members and thence forcedinto the slot, the extremities of said end spring members beingretracted to an isolated position in a subsequent engaged and lockedstate of said plate members which is the normal operating mode of themonitoring apparatus whereby the yarn material may be threaded into thesensor head without stopping the longitudinal motion of the yarn. i 3.In the apparatus set forth in claim 2 wherein said central and endspring members are formed from a single piece of metal, and v the slotis straight and provided with flared ends for ease of entrance and exitof the yarn material in its passage through the channel.

4. In an apparatus for monitoring a selected parameter of a small crosssection, continuous material suitable for passage through an improvedsensor head component of the apparatus, the improved sensor headcomprising,

a slotted plate member having a first slotted surface,

a cover plate member having a first nonslotted surface,

means for alternately engaging in mating relationship and separating thefirst surfaces of said slotted and cover plate members to thereby form achannel between said plate members in the engaged state thereof,

said alternately engaging and separating means comprising a toggle clampproviding a hold-down action in the engaged state thereof,

said toggle clamp comprising an actuating member, an actuated membercoupled to said actuating member and comprising a lever arm having adriven end connected to said cover plate member at a surface thereofopposite from said first nonslotted surface,

a nonmovable base having a fulcrum end of said lever arm connectedthereto, said nonmovable base connected to said slotted plate member ata surface thereof opposite from said first slotted surface,

means for mounting said slotted plate member in a stationary positionwhereby said cover plate member is alternately operated by said leverarm of said toggle clamp to provide engagement with and separation fromsaid slotted plate member supported in a fixed position,

means for supplying a pressurized fluid to said channel centrallythereof, said channel being enclosed along its sides in the engagedstate of said plate members except for a port supplying the pressurizedfluid into said channel, said channel adapted for passage of a smallcross section, continuous material therethrough whereby the pressurizedfluid upon issuance from said port restrictively flows' along saidchannel from the center to the ends thereof, the back pressure inducedat said port resulting from the restriction caused by the materialpassing through said channel being proportional to the magnitude of aselected parameter of the material being monitored by the apparatus,

a spring device comprising a central spring member retained between thesurface of said cover plate member opposite from said first nonslottedsurface thereof and said driven end of said lever arm of said toggleclamp, and

a pair of end spring members connected at opposite ends of said centralspring member and extending beyond sides of said slotted and cover platemembers wherein the ends of said channel are disposed, the extremitiesof said end spring members being concave-shaped and in an isolatedposition spaced from the longitudinal axis of said slot in said slottedplate member during the separated state of said plate members and beingforced toward and beyond the axis in an initial engaged state wherebythe strands of a multi-strand yarn material being threaded into thesensor had are collected by the concave-shaped extremities of said endspring members and thence forced into said means for retaining saidendspring members and central spring member in alignment parallel withthe longitudinal axis of the slot to insure the concave-shapedextremities of said end spring members being properly aligned with theyarn material in the initial engaged state of said plate members forproper collection of the strands of the yarn material.

2 3 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,667,282 Dated ne 6, 1972 Inventor(s) Bert J. Czwakiel and Donald F.Miller It is certified that error appears in the above-identified patentand that said Letters Patent are hereby corrected as shown below:

Claim 1, line 21, ''he" should be the Claim line 55, "had" should behead Signed and sealed this 6th day of March 1973.

(SEAL) Attest:

HER JR. 7 ROBERT GOTTSCHALK EDWARD M FLETC Commissioner of PatentsAttesting Officer

1. In an apparatus for monitoring a selected parameter of a small crosssection, continuous material suitable for passage through an improvedsensor had component of the apparatus, the improved sensor headcomprising, a slotted plate member having a first slotted surface, acover plate member having a first nonslotted surface, means foralternately engaging in mating relationship and separating the firstsurfaces of said slotted and cover plate members to thereby form achannel between said plate members in the engaged state thereof, meansfor supplying a pressurized fluid to said channel centrally thereof,said channel being enclosed along its sides in the engaged state of saidplate members except for a port supplying the pressurized fluid intosaid channel, said channel adapted for passage of a small cross section,continuous material therethrough whereby the pressurized fluid uponissuance from said port restrictively flows along said channel from thecenter to the ends thereof, the back pressure induced at said portresulting from the restriction caused by the material passing throughsaid channel being proportional to he magnitude of a selected parameterof the material being monitored by the apparatus, means for collectingthe strands of a multi-strand yarn material being monitored by theapparatus and for forcing the collected strands into said slot in saidslotted plate member, and said strand collecting and forcing means beingretained on said cover plate member on a surface thereof opposite fromthe first nonslotted surface, said strand collecting and forcing meansbeing operative with operation of said alternately engaging andseparating means.
 2. The apparatus set forth in claim 1 wherein saidstrand collecting and forcing means comprises a spring device includinga central spring member retained between the surface of said cover platemember opposite from the first nonslotted surface thereof and anactuated member of said alternately engaging and separating means, and apair of end spring members connected at opposite ends of said centralspring member and extending beyond sides of the slotted and cover platemembers wherein the ends of the channel are disposed, the extremities ofsaid end spring members being concave-shaped and in an isolated positionspaced from the longitudinal axis of the slot during the separated stateof said plate members and being forced toward and beyond the axis in aninitial engaged state whereby the strands of the multi-strand yarnmaterial being threaded into the sensor head are collected by theconcave-shaped extremeties of said end spring members and thence forcedinto the slot, the extremities of said end spring members beingretracted to an isolated position in a subsequent engaged and lockedstate of said plate members which is the normal operating mode of themonitoring apparatus whereby the yarn material may be threaded into thesensor head without stopping the longitudinal motion of the yarn.
 3. Inthe apparatus set forth in claim 2 wherein said central and end springmembers are formed from a single piece of metal, and the slot isstraight and provided with flared ends for ease of entrance and exit ofthe yarn material in its passage through the channel.
 4. In an apparatusfor monitoring a selected parameter of a small cross section, continuousmaterial suitable for passage through an improved sensor head componentof the apparatus, the improved sensor head comprising, a slotted platemember having a first slotted surface, a cover plate member having afirst nonslotted surface, means for alternately engaging in matingrelationship and separating the first surfaces of said slotted and coverplate members to thereby form a channel between said plate members inthe engaged state thereof, said alternately engaging and separatingmeans comprising a toggle clamp providing a hold-down action in theengaged state thereof, said toggle clamp comprising an actuating member,an actuated member coupled to said actuating member and comprising alever arm having a driven end connected to said cover plate member at asurface thereof opposite from said first nonslotted surface, anonmovable base having a fulcrum end of said lever arm connectedthereto, said nonmovable base connected to said slotted plate member ata surface thereof opposite from said first slotted surface, means formounting said slotted plate member in a stationary position whereby saidcover plate member is alternately operated by said lever arm of saidtoggle clamp to provide engagement with and separation from said slottedplate member supported in a fixed position, means for supplying apressurized fluid to said channel centrally thereof, said channel beingenclosed along its sides in the engaged state of said plate membersexcept for a port supplying the pressurized fluid into said channel,said channel adapted for passage of a small cross section, continuousmaterial therethrough whereby the pressurized fluid upon issuance fromsaid port restrictively flows along said channel from the center to theends thereof, the back pressure induced at said port resulting from therestriction caused by the material passing through said channel beingproportional to the magnitude of a selected parameter of the materialbeing monitored by the apparatus, a spring device comprising a centralspring member retained between the surface of said cover plate memberopposite from said first nonslotted surface thereof and said driven endof said lever arm of said toggle clamp, and a pair of end spring membersconnected at opposite ends of said central spring member and extendingbeyond sides of said slotted and cover plate members wherein the ends ofsaid channel are disposed, the extremities of said end spring membersbeing concave-shaped and in an isolated position spaced from thelongitudinal axis of said slot in said slotted plate member during theseparated state of said plate members and being forced toward and beyondthe axis in an initial engaged state whereby the strands of amulti-strand yarn material being threaded into the sensor had arecollected by the concave-shaped extremities of said end spring membersand thence forced into said slot in said slotted plate member, theextremities of said end spring members being retracted to an isolatedposition in a subsequent engaged and locked state of said plate memberswhich is the normal operating mode of the sensor head whereby the yarnmaterial may be threaded into the sensor head without stopping thelongitudinal motion of the yarn.
 5. In the apparatus set forth in claim4 wherein said spring device further comprises means for retaining saidend spring members and central spring member in alignment parallel withthe longitudinal axis of the slot to insure the concave-shapedextremities of said end spring members being properly aligned with theyarn material in the initial engaged state of said plate members forproper collection of the strands of the yarn material.